=(-1/2)*(4-x^2)^(3/2)/(3/2)|^(2)_(0)=
=-(1/3)*sqrt((4-x^2)^3)|^2_(0)=
=-(1/3)*0+(1/3)*sqrt(4^3)=
=(1/3)*4=4/3
Применили табличный интеграл
∫ x^(1/2)dx=x^(3/2)/(3/2)
для сложной функции
∫ [b]u[/b]^(1/2)d[b]u[/b]=[b]u[/b]^(3/2)/(3/2)
u=4-x^2
du=-2xdx
xdx=(-1/2)du
xdx=(-1/2)d(4-x^2)